Publication:

Fistula-in-ano in children under three: patterns, outcomes and imaging insights

Background The incidence of fistula-in-ano (FIA) in the pediatric population is not well established, despite its relatively common occurrence as a perianal disease. The aim of this study is to describe the proportions of simple and complex FIA in young children and to evaluate the treatment strategies applied.

Methods Children under 3 years of age who were treated for FIA at Amsterdam UMC between January 2012 until April 2021 were included in this retrospective study. The primary endpoints were the proportions simple and complex FIA and the applied treatment strategies. Secondary endpoints were postoperative complications, recurrences, and the diagnostic value of imaging studies performed.

Results Eighty-one patients were included, all male, with a median age of 9.2 months (range 1-36 months). Spontaneous resolution occurred in 19 patients (23.5%) prior to surgery. Sixty-two patients (76.5%) underwent surgical exploration: simple FIA in 85.5% (53/62), complex FIA in 8.1% (5/62), and healed fistula in 6.5% (4/62). No postoperative complications were observed. Recurrence occurred in 10 patients (16.1%).

Conclusions Spontaneous resolution occurred in 23.5% of children under 3 years with FIA. Among those undergoing surgery, more than 85% had simple FIA, with a recurrence rate of 16%. These findings highlight that conservative management may be appropriate in a subset of young children with FIA, while surgery is effective for the majority of cases. Routine preoperative imaging and follow-up for inflammatory bowel disease (IBD) appear unnecessary in this age group, except in cases of recurrent or persistent symptoms.